Because it's very, very unlikely that an LRT--any LRT--could handle the huge demand for transit on that corridor. I have no a priori problem with LRT...but if there's anywhere that passenger densities require heavy rail, it's south of Bloor.
You mean per trip? The LRT set in the rail corridors (Weston Galt SUB and Kingston SUB) could be three cars long each with the capacity to hold upto 200 commuters. If routed by a subway, every 90 seconds, it's likely LRTs could meet the demand. And of course LRTs can be routed undergrounf through the CBD area like other light rail systems do in Europe/US.
I'm not sure that you're aware of what can be done...you're basing your argument on the relative cost of transit projects but then you completely fudge the numbers. Why on earth would a Sheppard extension cost that much? The Spadina extension to Hwy 7 is slightly longer but is projected, after inflation and with vehicles, to cost $2.6 billion, and that includes a full half billion dollars of padding, not to mention tunnelling through largely empty land, elaborate stations, etc. The cost would be lowered even further if multiple subway projects were underway so that we didn't have to reinvent the wheel every time. Transit City, projected to cost over $8 billion, is hardly a cheap alternative.
You have a point. I thought extending Sheppard would cost more becuase it'd be more complicated to construct than the Richmond Hill extension. Remember though RHC would run in a straight line to the 407 and only comprise 4-6 stations max. Sheppard has the dubious task of crossing not one but two highway systems, rail junction and somehow be centric enough for the whole STC area (under the pretense of SRT closing down whereby McCowan station's obcelete). The way the TTC builds subways nowaways makes me skeptical that it'd be cost-effective to trod on.
Transit City (at least parts of it) could be well worth the $8 billion. Even Sheppard/STC itself is appeased somewhat given that a LRT stop at McCowan is 5 mins away from STC. Malvernites would also avoid STC and take Sheppard straight across instead. That way the SRT to Morningside Hts plan can be shelved and instead have BD extended to STC serving more people.
A subway extension to Pearson isn't worth building, not when some kind of train can connect the airport with downtown along the Weston rail corridor in less than half the time it'd take by TTC. If I did build a subway to the airport, it would be a branch/extension of the Bloor line.
There's some potential benefit to replacing the 192 with a subway line. For one, maybe Mississaugans have been going about things all wrong. Maybe instead of linking BD to Square One via Dundas Street, perhaps the true path to MCC is via the Eglinton/403 corridor. Apart from a commercial strip (c'mon guys everywhere has shops, does it really take a subway to reach them?) there's nothing of significance in that part of the world demanding subways.
Via the 427/Renforth mid-blocks could occur at Cloverdale Mall, Etobicoke Civic Centre (Vahalla Business Park, other office tower clusters), Burnhamthrope, Rathburn, Eringate and at Eglinton/Renforth/Matheson/Commerce (of course the Airport Corporate Centre). To Pearson Stn the BD line could run above ground until on airport property settling into Terminal 3 or 1. Commuter rail could work as well via a wye of the Georgetown GO line.
Most world cities have or recognize the importance of connecting their airports to heavy rail mass transit. Even Montreal's Blue Line is slated to eventually reach Trudeau Int'l. That's why I'm so disappointed that no one is even considering this for Toronto. Isn't it like 60, 000 commuter trips through Pearson everyday? Subways should be tapping into that market.